The first thing everyone wants to know when the buy a second hand GT BMX is ‘how old is it?’ Reading the GT serial number and finding out the build date is an important part of any BMX restoration. Once you now when the old GT BMX bike was built it’s much easier to find out what model it is and also look at the original parts lists and colours from the bike makers catalogues. A while back I spend some time investigating how to read mid-school and new school serial numbers on Mongoose BMX bikes. After buying and restoring a number of older mid-school and new school GT BMX bikes I also need to to figure out how to crack...